net/ipv4/fib_semantics.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              IPv4 Forwarding Information Base: semantics.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/uaccess.h>
  13 #include <linux/bitops.h>
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/mm.h>
  18 #include <linux/string.h>
  19 #include <linux/socket.h>
  20 #include <linux/sockios.h>
  21 #include <linux/errno.h>
  22 #include <linux/in.h>
  23 #include <linux/inet.h>
  24 #include <linux/inetdevice.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/init.h>
  30 #include <linux/slab.h>
  31 #include <linux/netlink.h>
  32 #include <linux/hash.h>
  33
  34 #include <net/arp.h>
  35 #include <net/inet_dscp.h>
  36 #include <net/ip.h>
  37 #include <net/protocol.h>
  38 #include <net/route.h>
  39 #include <net/tcp.h>
  40 #include <net/sock.h>
  41 #include <net/ip_fib.h>
  42 #include <net/ip6_fib.h>
  43 #include <net/nexthop.h>
  44 #include <net/netlink.h>
  45 #include <net/rtnh.h>
  46 #include <net/lwtunnel.h>
  47 #include <net/fib_notifier.h>
  48 #include <net/addrconf.h>
  49
  50 #include "fib_lookup.h"
  51
  52 static DEFINE_SPINLOCK(fib_info_lock);
  53 static struct hlist_head *fib_info_hash;
  54 static struct hlist_head *fib_info_laddrhash;
  55 static unsigned int fib_info_hash_size;
  56 static unsigned int fib_info_hash_bits;
  57 static unsigned int fib_info_cnt;
  58
  59 #define DEVINDEX_HASHBITS 8
  60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  62
  63 /* for_nexthops and change_nexthops only used when nexthop object
  64  * is not set in a fib_info. The logic within can reference fib_nh.
  65  */
  66 #ifdef CONFIG_IP_ROUTE_MULTIPATH
  67
  68 #define for_nexthops(fi) {                                              \
  69         int nhsel; const struct fib_nh *nh;                             \
  70         for (nhsel = 0, nh = (fi)->fib_nh;                              \
  71              nhsel < fib_info_num_path((fi));                           \
  72              nh++, nhsel++)
  73
  74 #define change_nexthops(fi) {                                           \
  75         int nhsel; struct fib_nh *nexthop_nh;                           \
  76         for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh);   \
  77              nhsel < fib_info_num_path((fi));                           \
  78              nexthop_nh++, nhsel++)
  79
  80 #else /* CONFIG_IP_ROUTE_MULTIPATH */
  81
  82 /* Hope, that gcc will optimize it to get rid of dummy loop */
  83
  84 #define for_nexthops(fi) {                                              \
  85         int nhsel; const struct fib_nh *nh = (fi)->fib_nh;              \
  86         for (nhsel = 0; nhsel < 1; nhsel++)
  87
  88 #define change_nexthops(fi) {                                           \
  89         int nhsel;                                                      \
  90         struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);    \
  91         for (nhsel = 0; nhsel < 1; nhsel++)
  92
  93 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
  94
  95 #define endfor_nexthops(fi) }
  96
  97
  98 const struct fib_prop fib_props[RTN_MAX + 1] = {
  99         [RTN_UNSPEC] = {
 100                 .error  = 0,
 101                 .scope  = RT_SCOPE_NOWHERE,
 102         },
 103         [RTN_UNICAST] = {
 104                 .error  = 0,
 105                 .scope  = RT_SCOPE_UNIVERSE,
 106         },
 107         [RTN_LOCAL] = {
 108                 .error  = 0,
 109                 .scope  = RT_SCOPE_HOST,
 110         },
 111         [RTN_BROADCAST] = {
 112                 .error  = 0,
 113                 .scope  = RT_SCOPE_LINK,
 114         },
 115         [RTN_ANYCAST] = {
 116                 .error  = 0,
 117                 .scope  = RT_SCOPE_LINK,
 118         },
 119         [RTN_MULTICAST] = {
 120                 .error  = 0,
 121                 .scope  = RT_SCOPE_UNIVERSE,
 122         },
 123         [RTN_BLACKHOLE] = {
 124                 .error  = -EINVAL,
 125                 .scope  = RT_SCOPE_UNIVERSE,
 126         },
 127         [RTN_UNREACHABLE] = {
 128                 .error  = -EHOSTUNREACH,
 129                 .scope  = RT_SCOPE_UNIVERSE,
 130         },
 131         [RTN_PROHIBIT] = {
 132                 .error  = -EACCES,
 133                 .scope  = RT_SCOPE_UNIVERSE,
 134         },
 135         [RTN_THROW] = {
 136                 .error  = -EAGAIN,
 137                 .scope  = RT_SCOPE_UNIVERSE,
 138         },
 139         [RTN_NAT] = {
 140                 .error  = -EINVAL,
 141                 .scope  = RT_SCOPE_NOWHERE,
 142         },
 143         [RTN_XRESOLVE] = {
 144                 .error  = -EINVAL,
 145                 .scope  = RT_SCOPE_NOWHERE,
 146         },
 147 };
 148
 149 static void rt_fibinfo_free(struct rtable __rcu **rtp)
 150 {
 151         struct rtable *rt = rcu_dereference_protected(*rtp, 1);
 152
 153         if (!rt)
 154                 return;
 155
 156         /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
 157          * because we waited an RCU grace period before calling
 158          * free_fib_info_rcu()
 159          */
 160
 161         dst_dev_put(&rt->dst);
 162         dst_release_immediate(&rt->dst);
 163 }
 164
 165 static void free_nh_exceptions(struct fib_nh_common *nhc)
 166 {
 167         struct fnhe_hash_bucket *hash;
 168         int i;
 169
 170         hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
 171         if (!hash)
 172                 return;
 173         for (i = 0; i < FNHE_HASH_SIZE; i++) {
 174                 struct fib_nh_exception *fnhe;
 175
 176                 fnhe = rcu_dereference_protected(hash[i].chain, 1);
 177                 while (fnhe) {
 178                         struct fib_nh_exception *next;
 179
 180                         next = rcu_dereference_protected(fnhe->fnhe_next, 1);
 181
 182                         rt_fibinfo_free(&fnhe->fnhe_rth_input);
 183                         rt_fibinfo_free(&fnhe->fnhe_rth_output);
 184
 185                         kfree(fnhe);
 186
 187                         fnhe = next;
 188                 }
 189         }
 190         kfree(hash);
 191 }
 192
 193 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 194 {
 195         int cpu;
 196
 197         if (!rtp)
 198                 return;
 199
 200         for_each_possible_cpu(cpu) {
 201                 struct rtable *rt;
 202
 203                 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
 204                 if (rt) {
 205                         dst_dev_put(&rt->dst);
 206                         dst_release_immediate(&rt->dst);
 207                 }
 208         }
 209         free_percpu(rtp);
 210 }
 211
 212 void fib_nh_common_release(struct fib_nh_common *nhc)
 213 {
 214         dev_put_track(nhc->nhc_dev, &nhc->nhc_dev_tracker);
 215         lwtstate_put(nhc->nhc_lwtstate);
 216         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 217         rt_fibinfo_free(&nhc->nhc_rth_input);
 218         free_nh_exceptions(nhc);
 219 }
 220 EXPORT_SYMBOL_GPL(fib_nh_common_release);
 221
 222 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 223 {
 224 #ifdef CONFIG_IP_ROUTE_CLASSID
 225         if (fib_nh->nh_tclassid)
 226                 atomic_dec(&net->ipv4.fib_num_tclassid_users);
 227 #endif
 228         fib_nh_common_release(&fib_nh->nh_common);
 229 }
 230
 231 /* Release a nexthop info record */
 232 static void free_fib_info_rcu(struct rcu_head *head)
 233 {
 234         struct fib_info *fi = container_of(head, struct fib_info, rcu);
 235
 236         if (fi->nh) {
 237                 nexthop_put(fi->nh);
 238         } else {
 239                 change_nexthops(fi) {
 240                         fib_nh_release(fi->fib_net, nexthop_nh);
 241                 } endfor_nexthops(fi);
 242         }
 243
 244         ip_fib_metrics_put(fi->fib_metrics);
 245
 246         kfree(fi);
 247 }
 248
 249 void free_fib_info(struct fib_info *fi)
 250 {
 251         if (fi->fib_dead == 0) {
 252                 pr_warn("Freeing alive fib_info %p\n", fi);
 253                 return;
 254         }
 255
 256         call_rcu(&fi->rcu, free_fib_info_rcu);
 257 }
 258 EXPORT_SYMBOL_GPL(free_fib_info);
 259
 260 void fib_release_info(struct fib_info *fi)
 261 {
 262         spin_lock_bh(&fib_info_lock);
 263         if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
 264                 hlist_del(&fi->fib_hash);
 265
 266                 /* Paired with READ_ONCE() in fib_create_info(). */
 267                 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
 268
 269                 if (fi->fib_prefsrc)
 270                         hlist_del(&fi->fib_lhash);
 271                 if (fi->nh) {
 272                         list_del(&fi->nh_list);
 273                 } else {
 274                         change_nexthops(fi) {
 275                                 if (!nexthop_nh->fib_nh_dev)
 276                                         continue;
 277                                 hlist_del(&nexthop_nh->nh_hash);
 278                         } endfor_nexthops(fi)
 279                 }
 280                 fi->fib_dead = 1;
 281                 fib_info_put(fi);
 282         }
 283         spin_unlock_bh(&fib_info_lock);
 284 }
 285
 286 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
 287 {
 288         const struct fib_nh *onh;
 289
 290         if (fi->nh || ofi->nh)
 291                 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
 292
 293         if (ofi->fib_nhs == 0)
 294                 return 0;
 295
 296         for_nexthops(fi) {
 297                 onh = fib_info_nh(ofi, nhsel);
 298
 299                 if (nh->fib_nh_oif != onh->fib_nh_oif ||
 300                     nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
 301                     nh->fib_nh_scope != onh->fib_nh_scope ||
 302 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 303                     nh->fib_nh_weight != onh->fib_nh_weight ||
 304 #endif
 305 #ifdef CONFIG_IP_ROUTE_CLASSID
 306                     nh->nh_tclassid != onh->nh_tclassid ||
 307 #endif
 308                     lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
 309                     ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
 310                         return -1;
 311
 312                 if (nh->fib_nh_gw_family == AF_INET &&
 313                     nh->fib_nh_gw4 != onh->fib_nh_gw4)
 314                         return -1;
 315
 316                 if (nh->fib_nh_gw_family == AF_INET6 &&
 317                     ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
 318                         return -1;
 319         } endfor_nexthops(fi);
 320         return 0;
 321 }
 322
 323 static inline unsigned int fib_devindex_hashfn(unsigned int val)
 324 {
 325         return hash_32(val, DEVINDEX_HASHBITS);
 326 }
 327
 328 static struct hlist_head *
 329 fib_info_devhash_bucket(const struct net_device *dev)
 330 {
 331         u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
 332
 333         return &fib_info_devhash[fib_devindex_hashfn(val)];
 334 }
 335
 336 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
 337                                       u32 prefsrc, u32 priority)
 338 {
 339         unsigned int val = init_val;
 340
 341         val ^= (protocol << 8) | scope;
 342         val ^= prefsrc;
 343         val ^= priority;
 344
 345         return val;
 346 }
 347
 348 static unsigned int fib_info_hashfn_result(unsigned int val)
 349 {
 350         unsigned int mask = (fib_info_hash_size - 1);
 351
 352         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 353 }
 354
 355 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 356 {
 357         unsigned int val;
 358
 359         val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
 360                                 fi->fib_scope, (__force u32)fi->fib_prefsrc,
 361                                 fi->fib_priority);
 362
 363         if (fi->nh) {
 364                 val ^= fib_devindex_hashfn(fi->nh->id);
 365         } else {
 366                 for_nexthops(fi) {
 367                         val ^= fib_devindex_hashfn(nh->fib_nh_oif);
 368                 } endfor_nexthops(fi)
 369         }
 370
 371         return fib_info_hashfn_result(val);
 372 }
 373
 374 /* no metrics, only nexthop id */
 375 static struct fib_info *fib_find_info_nh(struct net *net,
 376                                          const struct fib_config *cfg)
 377 {
 378         struct hlist_head *head;
 379         struct fib_info *fi;
 380         unsigned int hash;
 381
 382         hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
 383                                  cfg->fc_protocol, cfg->fc_scope,
 384                                  (__force u32)cfg->fc_prefsrc,
 385                                  cfg->fc_priority);
 386         hash = fib_info_hashfn_result(hash);
 387         head = &fib_info_hash[hash];
 388
 389         hlist_for_each_entry(fi, head, fib_hash) {
 390                 if (!net_eq(fi->fib_net, net))
 391                         continue;
 392                 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
 393                         continue;
 394                 if (cfg->fc_protocol == fi->fib_protocol &&
 395                     cfg->fc_scope == fi->fib_scope &&
 396                     cfg->fc_prefsrc == fi->fib_prefsrc &&
 397                     cfg->fc_priority == fi->fib_priority &&
 398                     cfg->fc_type == fi->fib_type &&
 399                     cfg->fc_table == fi->fib_tb_id &&
 400                     !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
 401                         return fi;
 402         }
 403
 404         return NULL;
 405 }
 406
 407 static struct fib_info *fib_find_info(struct fib_info *nfi)
 408 {
 409         struct hlist_head *head;
 410         struct fib_info *fi;
 411         unsigned int hash;
 412
 413         hash = fib_info_hashfn(nfi);
 414         head = &fib_info_hash[hash];
 415
 416         hlist_for_each_entry(fi, head, fib_hash) {
 417                 if (!net_eq(fi->fib_net, nfi->fib_net))
 418                         continue;
 419                 if (fi->fib_nhs != nfi->fib_nhs)
 420                         continue;
 421                 if (nfi->fib_protocol == fi->fib_protocol &&
 422                     nfi->fib_scope == fi->fib_scope &&
 423                     nfi->fib_prefsrc == fi->fib_prefsrc &&
 424                     nfi->fib_priority == fi->fib_priority &&
 425                     nfi->fib_type == fi->fib_type &&
 426                     memcmp(nfi->fib_metrics, fi->fib_metrics,
 427                            sizeof(u32) * RTAX_MAX) == 0 &&
 428                     !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 429                     nh_comp(fi, nfi) == 0)
 430                         return fi;
 431         }
 432
 433         return NULL;
 434 }
 435
 436 /* Check, that the gateway is already configured.
 437  * Used only by redirect accept routine.
 438  */
 439 int ip_fib_check_default(__be32 gw, struct net_device *dev)
 440 {
 441         struct hlist_head *head;
 442         struct fib_nh *nh;
 443
 444         spin_lock(&fib_info_lock);
 445
 446         head = fib_info_devhash_bucket(dev);
 447
 448         hlist_for_each_entry(nh, head, nh_hash) {
 449                 if (nh->fib_nh_dev == dev &&
 450                     nh->fib_nh_gw4 == gw &&
 451                     !(nh->fib_nh_flags & RTNH_F_DEAD)) {
 452                         spin_unlock(&fib_info_lock);
 453                         return 0;
 454                 }
 455         }
 456
 457         spin_unlock(&fib_info_lock);
 458
 459         return -1;
 460 }
 461
 462 size_t fib_nlmsg_size(struct fib_info *fi)
 463 {
 464         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 465                          + nla_total_size(4) /* RTA_TABLE */
 466                          + nla_total_size(4) /* RTA_DST */
 467                          + nla_total_size(4) /* RTA_PRIORITY */
 468                          + nla_total_size(4) /* RTA_PREFSRC */
 469                          + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 470         unsigned int nhs = fib_info_num_path(fi);
 471
 472         /* space for nested metrics */
 473         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 474
 475         if (fi->nh)
 476                 payload += nla_total_size(4); /* RTA_NH_ID */
 477
 478         if (nhs) {
 479                 size_t nh_encapsize = 0;
 480                 /* Also handles the special case nhs == 1 */
 481
 482                 /* each nexthop is packed in an attribute */
 483                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 484                 unsigned int i;
 485
 486                 /* may contain flow and gateway attribute */
 487                 nhsize += 2 * nla_total_size(4);
 488
 489                 /* grab encap info */
 490                 for (i = 0; i < fib_info_num_path(fi); i++) {
 491                         struct fib_nh_common *nhc = fib_info_nhc(fi, i);
 492
 493                         if (nhc->nhc_lwtstate) {
 494                                 /* RTA_ENCAP_TYPE */
 495                                 nh_encapsize += lwtunnel_get_encap_size(
 496                                                 nhc->nhc_lwtstate);
 497                                 /* RTA_ENCAP */
 498                                 nh_encapsize +=  nla_total_size(2);
 499                         }
 500                 }
 501
 502                 /* all nexthops are packed in a nested attribute */
 503                 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
 504
 505         }
 506
 507         return payload;
 508 }
 509
 510 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 511                int dst_len, u32 tb_id, const struct nl_info *info,
 512                unsigned int nlm_flags)
 513 {
 514         struct fib_rt_info fri;
 515         struct sk_buff *skb;
 516         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 517         int err = -ENOBUFS;
 518
 519         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 520         if (!skb)
 521                 goto errout;
 522
 523         fri.fi = fa->fa_info;
 524         fri.tb_id = tb_id;
 525         fri.dst = key;
 526         fri.dst_len = dst_len;
 527         fri.tos = inet_dscp_to_dsfield(fa->fa_dscp);
 528         fri.type = fa->fa_type;
 529         fri.offload = READ_ONCE(fa->offload);
 530         fri.trap = READ_ONCE(fa->trap);
 531         fri.offload_failed = READ_ONCE(fa->offload_failed);
 532         err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
 533         if (err < 0) {
 534                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 535                 WARN_ON(err == -EMSGSIZE);
 536                 kfree_skb(skb);
 537                 goto errout;
 538         }
 539         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 540                     info->nlh, GFP_KERNEL);
 541         return;
 542 errout:
 543         if (err < 0)
 544                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 545 }
 546
 547 static int fib_detect_death(struct fib_info *fi, int order,
 548                             struct fib_info **last_resort, int *last_idx,
 549                             int dflt)
 550 {
 551         const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 552         struct neighbour *n;
 553         int state = NUD_NONE;
 554
 555         if (likely(nhc->nhc_gw_family == AF_INET))
 556                 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 557         else if (nhc->nhc_gw_family == AF_INET6)
 558                 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 559                                  nhc->nhc_dev);
 560         else
 561                 n = NULL;
 562
 563         if (n) {
 564                 state = n->nud_state;
 565                 neigh_release(n);
 566         } else {
 567                 return 0;
 568         }
 569         if (state == NUD_REACHABLE)
 570                 return 0;
 571         if ((state & NUD_VALID) && order != dflt)
 572                 return 0;
 573         if ((state & NUD_VALID) ||
 574             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 575                 *last_resort = fi;
 576                 *last_idx = order;
 577         }
 578         return 1;
 579 }
 580
 581 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 582                        struct nlattr *encap, u16 encap_type,
 583                        void *cfg, gfp_t gfp_flags,
 584                        struct netlink_ext_ack *extack)
 585 {
 586         int err;
 587
 588         nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 589                                                     gfp_flags);
 590         if (!nhc->nhc_pcpu_rth_output)
 591                 return -ENOMEM;
 592
 593         if (encap) {
 594                 struct lwtunnel_state *lwtstate;
 595
 596                 if (encap_type == LWTUNNEL_ENCAP_NONE) {
 597                         NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 598                         err = -EINVAL;
 599                         goto lwt_failure;
 600                 }
 601                 err = lwtunnel_build_state(net, encap_type, encap,
 602                                            nhc->nhc_family, cfg, &lwtstate,
 603                                            extack);
 604                 if (err)
 605                         goto lwt_failure;
 606
 607                 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 608         }
 609
 610         return 0;
 611
 612 lwt_failure:
 613         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 614         nhc->nhc_pcpu_rth_output = NULL;
 615         return err;
 616 }
 617 EXPORT_SYMBOL_GPL(fib_nh_common_init);
 618
 619 int fib_nh_init(struct net *net, struct fib_nh *nh,
 620                 struct fib_config *cfg, int nh_weight,
 621                 struct netlink_ext_ack *extack)
 622 {
 623         int err;
 624
 625         nh->fib_nh_family = AF_INET;
 626
 627         err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
 628                                  cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 629         if (err)
 630                 return err;
 631
 632         nh->fib_nh_oif = cfg->fc_oif;
 633         nh->fib_nh_gw_family = cfg->fc_gw_family;
 634         if (cfg->fc_gw_family == AF_INET)
 635                 nh->fib_nh_gw4 = cfg->fc_gw4;
 636         else if (cfg->fc_gw_family == AF_INET6)
 637                 nh->fib_nh_gw6 = cfg->fc_gw6;
 638
 639         nh->fib_nh_flags = cfg->fc_flags;
 640
 641 #ifdef CONFIG_IP_ROUTE_CLASSID
 642         nh->nh_tclassid = cfg->fc_flow;
 643         if (nh->nh_tclassid)
 644                 atomic_inc(&net->ipv4.fib_num_tclassid_users);
 645 #endif
 646 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 647         nh->fib_nh_weight = nh_weight;
 648 #endif
 649         return 0;
 650 }
 651
 652 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 653
 654 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 655                               struct netlink_ext_ack *extack)
 656 {
 657         int nhs = 0;
 658
 659         while (rtnh_ok(rtnh, remaining)) {
 660                 nhs++;
 661                 rtnh = rtnh_next(rtnh, &remaining);
 662         }
 663
 664         /* leftover implies invalid nexthop configuration, discard it */
 665         if (remaining > 0) {
 666                 NL_SET_ERR_MSG(extack,
 667                                "Invalid nexthop configuration - extra data after nexthops");
 668                 nhs = 0;
 669         }
 670
 671         return nhs;
 672 }
 673
 674 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
 675                             struct netlink_ext_ack *extack)
 676 {
 677         if (nla_len(nla) < sizeof(*gw)) {
 678                 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
 679                 return -EINVAL;
 680         }
 681
 682         *gw = nla_get_in_addr(nla);
 683
 684         return 0;
 685 }
 686
 687 /* only called when fib_nh is integrated into fib_info */
 688 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 689                        int remaining, struct fib_config *cfg,
 690                        struct netlink_ext_ack *extack)
 691 {
 692         struct net *net = fi->fib_net;
 693         struct fib_config fib_cfg;
 694         struct fib_nh *nh;
 695         int ret;
 696
 697         change_nexthops(fi) {
 698                 int attrlen;
 699
 700                 memset(&fib_cfg, 0, sizeof(fib_cfg));
 701
 702                 if (!rtnh_ok(rtnh, remaining)) {
 703                         NL_SET_ERR_MSG(extack,
 704                                        "Invalid nexthop configuration - extra data after nexthop");
 705                         return -EINVAL;
 706                 }
 707
 708                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 709                         NL_SET_ERR_MSG(extack,
 710                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 711                         return -EINVAL;
 712                 }
 713
 714                 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 715                 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 716
 717                 attrlen = rtnh_attrlen(rtnh);
 718                 if (attrlen > 0) {
 719                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 720
 721                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 722                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 723                         if (nla && nlav) {
 724                                 NL_SET_ERR_MSG(extack,
 725                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 726                                 return -EINVAL;
 727                         }
 728                         if (nla) {
 729                                 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
 730                                                        extack);
 731                                 if (ret)
 732                                         goto errout;
 733
 734                                 if (fib_cfg.fc_gw4)
 735                                         fib_cfg.fc_gw_family = AF_INET;
 736                         } else if (nlav) {
 737                                 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 738                                 if (ret)
 739                                         goto errout;
 740                         }
 741
 742                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 743                         if (nla) {
 744                                 if (nla_len(nla) < sizeof(u32)) {
 745                                         NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
 746                                         return -EINVAL;
 747                                 }
 748                                 fib_cfg.fc_flow = nla_get_u32(nla);
 749                         }
 750
 751                         fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 752                         /* RTA_ENCAP_TYPE length checked in
 753                          * lwtunnel_valid_encap_type_attr
 754                          */
 755                         nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 756                         if (nla)
 757                                 fib_cfg.fc_encap_type = nla_get_u16(nla);
 758                 }
 759
 760                 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 761                                   rtnh->rtnh_hops + 1, extack);
 762                 if (ret)
 763                         goto errout;
 764
 765                 rtnh = rtnh_next(rtnh, &remaining);
 766         } endfor_nexthops(fi);
 767
 768         ret = -EINVAL;
 769         nh = fib_info_nh(fi, 0);
 770         if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 771                 NL_SET_ERR_MSG(extack,
 772                                "Nexthop device index does not match RTA_OIF");
 773                 goto errout;
 774         }
 775         if (cfg->fc_gw_family) {
 776                 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 777                     (cfg->fc_gw_family == AF_INET &&
 778                      nh->fib_nh_gw4 != cfg->fc_gw4) ||
 779                     (cfg->fc_gw_family == AF_INET6 &&
 780                      ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 781                         NL_SET_ERR_MSG(extack,
 782                                        "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 783                         goto errout;
 784                 }
 785         }
 786 #ifdef CONFIG_IP_ROUTE_CLASSID
 787         if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 788                 NL_SET_ERR_MSG(extack,
 789                                "Nexthop class id does not match RTA_FLOW");
 790                 goto errout;
 791         }
 792 #endif
 793         ret = 0;
 794 errout:
 795         return ret;
 796 }
 797
 798 /* only called when fib_nh is integrated into fib_info */
 799 static void fib_rebalance(struct fib_info *fi)
 800 {
 801         int total;
 802         int w;
 803
 804         if (fib_info_num_path(fi) < 2)
 805                 return;
 806
 807         total = 0;
 808         for_nexthops(fi) {
 809                 if (nh->fib_nh_flags & RTNH_F_DEAD)
 810                         continue;
 811
 812                 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 813                     nh->fib_nh_flags & RTNH_F_LINKDOWN)
 814                         continue;
 815
 816                 total += nh->fib_nh_weight;
 817         } endfor_nexthops(fi);
 818
 819         w = 0;
 820         change_nexthops(fi) {
 821                 int upper_bound;
 822
 823                 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 824                         upper_bound = -1;
 825                 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 826                            nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 827                         upper_bound = -1;
 828                 } else {
 829                         w += nexthop_nh->fib_nh_weight;
 830                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 831                                                             total) - 1;
 832                 }
 833
 834                 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 835         } endfor_nexthops(fi);
 836 }
 837 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 838
 839 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 840                        int remaining, struct fib_config *cfg,
 841                        struct netlink_ext_ack *extack)
 842 {
 843         NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 844
 845         return -EINVAL;
 846 }
 847
 848 #define fib_rebalance(fi) do { } while (0)
 849
 850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 851
 852 static int fib_encap_match(struct net *net, u16 encap_type,
 853                            struct nlattr *encap,
 854                            const struct fib_nh *nh,
 855                            const struct fib_config *cfg,
 856                            struct netlink_ext_ack *extack)
 857 {
 858         struct lwtunnel_state *lwtstate;
 859         int ret, result = 0;
 860
 861         if (encap_type == LWTUNNEL_ENCAP_NONE)
 862                 return 0;
 863
 864         ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
 865                                    cfg, &lwtstate, extack);
 866         if (!ret) {
 867                 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 868                 lwtstate_free(lwtstate);
 869         }
 870
 871         return result;
 872 }
 873
 874 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
 875                  struct netlink_ext_ack *extack)
 876 {
 877 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 878         struct rtnexthop *rtnh;
 879         int remaining;
 880 #endif
 881
 882         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 883                 return 1;
 884
 885         if (cfg->fc_nh_id) {
 886                 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 887                         return 0;
 888                 return 1;
 889         }
 890
 891         if (cfg->fc_oif || cfg->fc_gw_family) {
 892                 struct fib_nh *nh;
 893
 894                 /* cannot match on nexthop object attributes */
 895                 if (fi->nh)
 896                         return 1;
 897
 898                 nh = fib_info_nh(fi, 0);
 899                 if (cfg->fc_encap) {
 900                         if (fib_encap_match(net, cfg->fc_encap_type,
 901                                             cfg->fc_encap, nh, cfg, extack))
 902                                 return 1;
 903                 }
 904 #ifdef CONFIG_IP_ROUTE_CLASSID
 905                 if (cfg->fc_flow &&
 906                     cfg->fc_flow != nh->nh_tclassid)
 907                         return 1;
 908 #endif
 909                 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 910                     (cfg->fc_gw_family &&
 911                      cfg->fc_gw_family != nh->fib_nh_gw_family))
 912                         return 1;
 913
 914                 if (cfg->fc_gw_family == AF_INET &&
 915                     cfg->fc_gw4 != nh->fib_nh_gw4)
 916                         return 1;
 917
 918                 if (cfg->fc_gw_family == AF_INET6 &&
 919                     ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 920                         return 1;
 921
 922                 return 0;
 923         }
 924
 925 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 926         if (!cfg->fc_mp)
 927                 return 0;
 928
 929         rtnh = cfg->fc_mp;
 930         remaining = cfg->fc_mp_len;
 931
 932         for_nexthops(fi) {
 933                 int attrlen;
 934
 935                 if (!rtnh_ok(rtnh, remaining))
 936                         return -EINVAL;
 937
 938                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 939                         return 1;
 940
 941                 attrlen = rtnh_attrlen(rtnh);
 942                 if (attrlen > 0) {
 943                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 944                         int err;
 945
 946                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 947                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 948                         if (nla && nlav) {
 949                                 NL_SET_ERR_MSG(extack,
 950                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 951                                 return -EINVAL;
 952                         }
 953
 954                         if (nla) {
 955                                 __be32 gw;
 956
 957                                 err = fib_gw_from_attr(&gw, nla, extack);
 958                                 if (err)
 959                                         return err;
 960
 961                                 if (nh->fib_nh_gw_family != AF_INET ||
 962                                     gw != nh->fib_nh_gw4)
 963                                         return 1;
 964                         } else if (nlav) {
 965                                 struct fib_config cfg2;
 966
 967                                 err = fib_gw_from_via(&cfg2, nlav, extack);
 968                                 if (err)
 969                                         return err;
 970
 971                                 switch (nh->fib_nh_gw_family) {
 972                                 case AF_INET:
 973                                         if (cfg2.fc_gw_family != AF_INET ||
 974                                             cfg2.fc_gw4 != nh->fib_nh_gw4)
 975                                                 return 1;
 976                                         break;
 977                                 case AF_INET6:
 978                                         if (cfg2.fc_gw_family != AF_INET6 ||
 979                                             ipv6_addr_cmp(&cfg2.fc_gw6,
 980                                                           &nh->fib_nh_gw6))
 981                                                 return 1;
 982                                         break;
 983                                 }
 984                         }
 985
 986 #ifdef CONFIG_IP_ROUTE_CLASSID
 987                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 988                         if (nla) {
 989                                 if (nla_len(nla) < sizeof(u32)) {
 990                                         NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
 991                                         return -EINVAL;
 992                                 }
 993                                 if (nla_get_u32(nla) != nh->nh_tclassid)
 994                                         return 1;
 995                         }
 996 #endif
 997                 }
 998
 999                 rtnh = rtnh_next(rtnh, &remaining);
1000         } endfor_nexthops(fi);
1001 #endif
1002         return 0;
1003 }
1004
1005 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1006 {
1007         struct nlattr *nla;
1008         int remaining;
1009
1010         if (!cfg->fc_mx)
1011                 return true;
1012
1013         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1014                 int type = nla_type(nla);
1015                 u32 fi_val, val;
1016
1017                 if (!type)
1018                         continue;
1019                 if (type > RTAX_MAX)
1020                         return false;
1021
1022                 if (type == RTAX_CC_ALGO) {
1023                         char tmp[TCP_CA_NAME_MAX];
1024                         bool ecn_ca = false;
1025
1026                         nla_strscpy(tmp, nla, sizeof(tmp));
1027                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1028                 } else {
1029                         if (nla_len(nla) != sizeof(u32))
1030                                 return false;
1031                         val = nla_get_u32(nla);
1032                 }
1033
1034                 fi_val = fi->fib_metrics->metrics[type - 1];
1035                 if (type == RTAX_FEATURES)
1036                         fi_val &= ~DST_FEATURE_ECN_CA;
1037
1038                 if (fi_val != val)
1039                         return false;
1040         }
1041
1042         return true;
1043 }
1044
1045 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1046                               u32 table, struct netlink_ext_ack *extack)
1047 {
1048         struct fib6_config cfg = {
1049                 .fc_table = table,
1050                 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1051                 .fc_ifindex = nh->fib_nh_oif,
1052                 .fc_gateway = nh->fib_nh_gw6,
1053         };
1054         struct fib6_nh fib6_nh = {};
1055         int err;
1056
1057         err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1058         if (!err) {
1059                 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1060                 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL);
1061                 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1062                 nh->fib_nh_scope = RT_SCOPE_LINK;
1063
1064                 ipv6_stub->fib6_nh_release(&fib6_nh);
1065         }
1066
1067         return err;
1068 }
1069
1070 /*
1071  * Picture
1072  * -------
1073  *
1074  * Semantics of nexthop is very messy by historical reasons.
1075  * We have to take into account, that:
1076  * a) gateway can be actually local interface address,
1077  *    so that gatewayed route is direct.
1078  * b) gateway must be on-link address, possibly
1079  *    described not by an ifaddr, but also by a direct route.
1080  * c) If both gateway and interface are specified, they should not
1081  *    contradict.
1082  * d) If we use tunnel routes, gateway could be not on-link.
1083  *
1084  * Attempt to reconcile all of these (alas, self-contradictory) conditions
1085  * results in pretty ugly and hairy code with obscure logic.
1086  *
1087  * I chose to generalized it instead, so that the size
1088  * of code does not increase practically, but it becomes
1089  * much more general.
1090  * Every prefix is assigned a "scope" value: "host" is local address,
1091  * "link" is direct route,
1092  * [ ... "site" ... "interior" ... ]
1093  * and "universe" is true gateway route with global meaning.
1094  *
1095  * Every prefix refers to a set of "nexthop"s (gw, oif),
1096  * where gw must have narrower scope. This recursion stops
1097  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1098  * which means that gw is forced to be on link.
1099  *
1100  * Code is still hairy, but now it is apparently logically
1101  * consistent and very flexible. F.e. as by-product it allows
1102  * to co-exists in peace independent exterior and interior
1103  * routing processes.
1104  *
1105  * Normally it looks as following.
1106  *
1107  * {universe prefix}  -> (gw, oif) [scope link]
1108  *                |
1109  *                |-> {link prefix} -> (gw, oif) [scope local]
1110  *                                      |
1111  *                                      |-> {local prefix} (terminal node)
1112  */
1113 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1114                               u8 scope, struct netlink_ext_ack *extack)
1115 {
1116         struct net_device *dev;
1117         struct fib_result res;
1118         int err = 0;
1119
1120         if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1121                 unsigned int addr_type;
1122
1123                 if (scope >= RT_SCOPE_LINK) {
1124                         NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1125                         return -EINVAL;
1126                 }
1127                 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1128                 if (!dev) {
1129                         NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1130                         return -ENODEV;
1131                 }
1132                 if (!(dev->flags & IFF_UP)) {
1133                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1134                         return -ENETDOWN;
1135                 }
1136                 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1137                 if (addr_type != RTN_UNICAST) {
1138                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139                         return -EINVAL;
1140                 }
1141                 if (!netif_carrier_ok(dev))
1142                         nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1143                 nh->fib_nh_dev = dev;
1144                 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1145                 nh->fib_nh_scope = RT_SCOPE_LINK;
1146                 return 0;
1147         }
1148         rcu_read_lock();
1149         {
1150                 struct fib_table *tbl = NULL;
1151                 struct flowi4 fl4 = {
1152                         .daddr = nh->fib_nh_gw4,
1153                         .flowi4_scope = scope + 1,
1154                         .flowi4_oif = nh->fib_nh_oif,
1155                         .flowi4_iif = LOOPBACK_IFINDEX,
1156                 };
1157
1158                 /* It is not necessary, but requires a bit of thinking */
1159                 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1160                         fl4.flowi4_scope = RT_SCOPE_LINK;
1161
1162                 if (table && table != RT_TABLE_MAIN)
1163                         tbl = fib_get_table(net, table);
1164
1165                 if (tbl)
1166                         err = fib_table_lookup(tbl, &fl4, &res,
1167                                                FIB_LOOKUP_IGNORE_LINKSTATE |
1168                                                FIB_LOOKUP_NOREF);
1169
1170                 /* on error or if no table given do full lookup. This
1171                  * is needed for example when nexthops are in the local
1172                  * table rather than the given table
1173                  */
1174                 if (!tbl || err) {
1175                         err = fib_lookup(net, &fl4, &res,
1176                                          FIB_LOOKUP_IGNORE_LINKSTATE);
1177                 }
1178
1179                 if (err) {
1180                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1181                         goto out;
1182                 }
1183         }
1184
1185         err = -EINVAL;
1186         if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1187                 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1188                 goto out;
1189         }
1190         nh->fib_nh_scope = res.scope;
1191         nh->fib_nh_oif = FIB_RES_OIF(res);
1192         nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1193         if (!dev) {
1194                 NL_SET_ERR_MSG(extack,
1195                                "No egress device for nexthop gateway");
1196                 goto out;
1197         }
1198         dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1199         if (!netif_carrier_ok(dev))
1200                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1201         err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1202 out:
1203         rcu_read_unlock();
1204         return err;
1205 }
1206
1207 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1208                               struct netlink_ext_ack *extack)
1209 {
1210         struct in_device *in_dev;
1211         int err;
1212
1213         if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1214                 NL_SET_ERR_MSG(extack,
1215                                "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1216                 return -EINVAL;
1217         }
1218
1219         rcu_read_lock();
1220
1221         err = -ENODEV;
1222         in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1223         if (!in_dev)
1224                 goto out;
1225         err = -ENETDOWN;
1226         if (!(in_dev->dev->flags & IFF_UP)) {
1227                 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1228                 goto out;
1229         }
1230
1231         nh->fib_nh_dev = in_dev->dev;
1232         dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1233         nh->fib_nh_scope = RT_SCOPE_HOST;
1234         if (!netif_carrier_ok(nh->fib_nh_dev))
1235                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1236         err = 0;
1237 out:
1238         rcu_read_unlock();
1239         return err;
1240 }
1241
1242 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1243                  struct netlink_ext_ack *extack)
1244 {
1245         int err;
1246
1247         if (nh->fib_nh_gw_family == AF_INET)
1248                 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1249         else if (nh->fib_nh_gw_family == AF_INET6)
1250                 err = fib_check_nh_v6_gw(net, nh, table, extack);
1251         else
1252                 err = fib_check_nh_nongw(net, nh, extack);
1253
1254         return err;
1255 }
1256
1257 static struct hlist_head *
1258 fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1259 {
1260         u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1261                            fib_info_hash_bits);
1262
1263         return &fib_info_laddrhash[slot];
1264 }
1265
1266 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1267                                struct hlist_head *new_laddrhash,
1268                                unsigned int new_size)
1269 {
1270         struct hlist_head *old_info_hash, *old_laddrhash;
1271         unsigned int old_size = fib_info_hash_size;
1272         unsigned int i;
1273
1274         spin_lock_bh(&fib_info_lock);
1275         old_info_hash = fib_info_hash;
1276         old_laddrhash = fib_info_laddrhash;
1277         fib_info_hash_size = new_size;
1278         fib_info_hash_bits = ilog2(new_size);
1279
1280         for (i = 0; i < old_size; i++) {
1281                 struct hlist_head *head = &fib_info_hash[i];
1282                 struct hlist_node *n;
1283                 struct fib_info *fi;
1284
1285                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1286                         struct hlist_head *dest;
1287                         unsigned int new_hash;
1288
1289                         new_hash = fib_info_hashfn(fi);
1290                         dest = &new_info_hash[new_hash];
1291                         hlist_add_head(&fi->fib_hash, dest);
1292                 }
1293         }
1294         fib_info_hash = new_info_hash;
1295
1296         fib_info_laddrhash = new_laddrhash;
1297         for (i = 0; i < old_size; i++) {
1298                 struct hlist_head *lhead = &old_laddrhash[i];
1299                 struct hlist_node *n;
1300                 struct fib_info *fi;
1301
1302                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1303                         struct hlist_head *ldest;
1304
1305                         ldest = fib_info_laddrhash_bucket(fi->fib_net,
1306                                                           fi->fib_prefsrc);
1307                         hlist_add_head(&fi->fib_lhash, ldest);
1308                 }
1309         }
1310
1311         spin_unlock_bh(&fib_info_lock);
1312
1313         kvfree(old_info_hash);
1314         kvfree(old_laddrhash);
1315 }
1316
1317 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1318                                  unsigned char scope)
1319 {
1320         struct fib_nh *nh;
1321
1322         if (nhc->nhc_family != AF_INET)
1323                 return inet_select_addr(nhc->nhc_dev, 0, scope);
1324
1325         nh = container_of(nhc, struct fib_nh, nh_common);
1326         nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1327         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1328
1329         return nh->nh_saddr;
1330 }
1331
1332 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1333 {
1334         struct fib_nh_common *nhc = res->nhc;
1335
1336         if (res->fi->fib_prefsrc)
1337                 return res->fi->fib_prefsrc;
1338
1339         if (nhc->nhc_family == AF_INET) {
1340                 struct fib_nh *nh;
1341
1342                 nh = container_of(nhc, struct fib_nh, nh_common);
1343                 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1344                         return nh->nh_saddr;
1345         }
1346
1347         return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1348 }
1349
1350 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1351 {
1352         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1353             fib_prefsrc != cfg->fc_dst) {
1354                 u32 tb_id = cfg->fc_table;
1355                 int rc;
1356
1357                 if (tb_id == RT_TABLE_MAIN)
1358                         tb_id = RT_TABLE_LOCAL;
1359
1360                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1361                                           fib_prefsrc, tb_id);
1362
1363                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1364                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1365                                                   fib_prefsrc, RT_TABLE_LOCAL);
1366                 }
1367
1368                 if (rc != RTN_LOCAL)
1369                         return false;
1370         }
1371         return true;
1372 }
1373
1374 struct fib_info *fib_create_info(struct fib_config *cfg,
1375                                  struct netlink_ext_ack *extack)
1376 {
1377         int err;
1378         struct fib_info *fi = NULL;
1379         struct nexthop *nh = NULL;
1380         struct fib_info *ofi;
1381         int nhs = 1;
1382         struct net *net = cfg->fc_nlinfo.nl_net;
1383
1384         if (cfg->fc_type > RTN_MAX)
1385                 goto err_inval;
1386
1387         /* Fast check to catch the most weird cases */
1388         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1389                 NL_SET_ERR_MSG(extack, "Invalid scope");
1390                 goto err_inval;
1391         }
1392
1393         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1394                 NL_SET_ERR_MSG(extack,
1395                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1396                 goto err_inval;
1397         }
1398
1399         if (cfg->fc_nh_id) {
1400                 if (!cfg->fc_mx) {
1401                         fi = fib_find_info_nh(net, cfg);
1402                         if (fi) {
1403                                 refcount_inc(&fi->fib_treeref);
1404                                 return fi;
1405                         }
1406                 }
1407
1408                 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1409                 if (!nh) {
1410                         NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1411                         goto err_inval;
1412                 }
1413                 nhs = 0;
1414         }
1415
1416 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1417         if (cfg->fc_mp) {
1418                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1419                 if (nhs == 0)
1420                         goto err_inval;
1421         }
1422 #endif
1423
1424         err = -ENOBUFS;
1425
1426         /* Paired with WRITE_ONCE() in fib_release_info() */
1427         if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1428                 unsigned int new_size = fib_info_hash_size << 1;
1429                 struct hlist_head *new_info_hash;
1430                 struct hlist_head *new_laddrhash;
1431                 size_t bytes;
1432
1433                 if (!new_size)
1434                         new_size = 16;
1435                 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1436                 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1437                 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1438                 if (!new_info_hash || !new_laddrhash) {
1439                         kvfree(new_info_hash);
1440                         kvfree(new_laddrhash);
1441                 } else {
1442                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1443                 }
1444                 if (!fib_info_hash_size)
1445                         goto failure;
1446         }
1447
1448         fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1449         if (!fi)
1450                 goto failure;
1451         fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1452                                               cfg->fc_mx_len, extack);
1453         if (IS_ERR(fi->fib_metrics)) {
1454                 err = PTR_ERR(fi->fib_metrics);
1455                 kfree(fi);
1456                 return ERR_PTR(err);
1457         }
1458
1459         fi->fib_net = net;
1460         fi->fib_protocol = cfg->fc_protocol;
1461         fi->fib_scope = cfg->fc_scope;
1462         fi->fib_flags = cfg->fc_flags;
1463         fi->fib_priority = cfg->fc_priority;
1464         fi->fib_prefsrc = cfg->fc_prefsrc;
1465         fi->fib_type = cfg->fc_type;
1466         fi->fib_tb_id = cfg->fc_table;
1467
1468         fi->fib_nhs = nhs;
1469         if (nh) {
1470                 if (!nexthop_get(nh)) {
1471                         NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1472                         err = -EINVAL;
1473                 } else {
1474                         err = 0;
1475                         fi->nh = nh;
1476                 }
1477         } else {
1478                 change_nexthops(fi) {
1479                         nexthop_nh->nh_parent = fi;
1480                 } endfor_nexthops(fi)
1481
1482                 if (cfg->fc_mp)
1483                         err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1484                                           extack);
1485                 else
1486                         err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1487         }
1488
1489         if (err != 0)
1490                 goto failure;
1491
1492         if (fib_props[cfg->fc_type].error) {
1493                 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1494                         NL_SET_ERR_MSG(extack,
1495                                        "Gateway, device and multipath can not be specified for this route type");
1496                         goto err_inval;
1497                 }
1498                 goto link_it;
1499         } else {
1500                 switch (cfg->fc_type) {
1501                 case RTN_UNICAST:
1502                 case RTN_LOCAL:
1503                 case RTN_BROADCAST:
1504                 case RTN_ANYCAST:
1505                 case RTN_MULTICAST:
1506                         break;
1507                 default:
1508                         NL_SET_ERR_MSG(extack, "Invalid route type");
1509                         goto err_inval;
1510                 }
1511         }
1512
1513         if (cfg->fc_scope > RT_SCOPE_HOST) {
1514                 NL_SET_ERR_MSG(extack, "Invalid scope");
1515                 goto err_inval;
1516         }
1517
1518         if (fi->nh) {
1519                 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1520                 if (err)
1521                         goto failure;
1522         } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1523                 struct fib_nh *nh = fi->fib_nh;
1524
1525                 /* Local address is added. */
1526                 if (nhs != 1) {
1527                         NL_SET_ERR_MSG(extack,
1528                                        "Route with host scope can not have multiple nexthops");
1529                         goto err_inval;
1530                 }
1531                 if (nh->fib_nh_gw_family) {
1532                         NL_SET_ERR_MSG(extack,
1533                                        "Route with host scope can not have a gateway");
1534                         goto err_inval;
1535                 }
1536                 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1537                 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1538                 err = -ENODEV;
1539                 if (!nh->fib_nh_dev)
1540                         goto failure;
1541                 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1542                                      GFP_KERNEL);
1543         } else {
1544                 int linkdown = 0;
1545
1546                 change_nexthops(fi) {
1547                         err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1548                                            cfg->fc_table, cfg->fc_scope,
1549                                            extack);
1550                         if (err != 0)
1551                                 goto failure;
1552                         if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1553                                 linkdown++;
1554                 } endfor_nexthops(fi)
1555                 if (linkdown == fi->fib_nhs)
1556                         fi->fib_flags |= RTNH_F_LINKDOWN;
1557         }
1558
1559         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1560                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1561                 goto err_inval;
1562         }
1563
1564         if (!fi->nh) {
1565                 change_nexthops(fi) {
1566                         fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1567                                                   fi->fib_scope);
1568                         if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1569                                 fi->fib_nh_is_v6 = true;
1570                 } endfor_nexthops(fi)
1571
1572                 fib_rebalance(fi);
1573         }
1574
1575 link_it:
1576         ofi = fib_find_info(fi);
1577         if (ofi) {
1578                 fi->fib_dead = 1;
1579                 free_fib_info(fi);
1580                 refcount_inc(&ofi->fib_treeref);
1581                 return ofi;
1582         }
1583
1584         refcount_set(&fi->fib_treeref, 1);
1585         refcount_set(&fi->fib_clntref, 1);
1586         spin_lock_bh(&fib_info_lock);
1587         fib_info_cnt++;
1588         hlist_add_head(&fi->fib_hash,
1589                        &fib_info_hash[fib_info_hashfn(fi)]);
1590         if (fi->fib_prefsrc) {
1591                 struct hlist_head *head;
1592
1593                 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1594                 hlist_add_head(&fi->fib_lhash, head);
1595         }
1596         if (fi->nh) {
1597                 list_add(&fi->nh_list, &nh->fi_list);
1598         } else {
1599                 change_nexthops(fi) {
1600                         struct hlist_head *head;
1601
1602                         if (!nexthop_nh->fib_nh_dev)
1603                                 continue;
1604                         head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1605                         hlist_add_head(&nexthop_nh->nh_hash, head);
1606                 } endfor_nexthops(fi)
1607         }
1608         spin_unlock_bh(&fib_info_lock);
1609         return fi;
1610
1611 err_inval:
1612         err = -EINVAL;
1613
1614 failure:
1615         if (fi) {
1616                 fi->fib_dead = 1;
1617                 free_fib_info(fi);
1618         }
1619
1620         return ERR_PTR(err);
1621 }
1622
1623 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1624                      u8 rt_family, unsigned char *flags, bool skip_oif)
1625 {
1626         if (nhc->nhc_flags & RTNH_F_DEAD)
1627                 *flags |= RTNH_F_DEAD;
1628
1629         if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1630                 *flags |= RTNH_F_LINKDOWN;
1631
1632                 rcu_read_lock();
1633                 switch (nhc->nhc_family) {
1634                 case AF_INET:
1635                         if (ip_ignore_linkdown(nhc->nhc_dev))
1636                                 *flags |= RTNH_F_DEAD;
1637                         break;
1638                 case AF_INET6:
1639                         if (ip6_ignore_linkdown(nhc->nhc_dev))
1640                                 *flags |= RTNH_F_DEAD;
1641                         break;
1642                 }
1643                 rcu_read_unlock();
1644         }
1645
1646         switch (nhc->nhc_gw_family) {
1647         case AF_INET:
1648                 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1649                         goto nla_put_failure;
1650                 break;
1651         case AF_INET6:
1652                 /* if gateway family does not match nexthop family
1653                  * gateway is encoded as RTA_VIA
1654                  */
1655                 if (rt_family != nhc->nhc_gw_family) {
1656                         int alen = sizeof(struct in6_addr);
1657                         struct nlattr *nla;
1658                         struct rtvia *via;
1659
1660                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
1661                         if (!nla)
1662                                 goto nla_put_failure;
1663
1664                         via = nla_data(nla);
1665                         via->rtvia_family = AF_INET6;
1666                         memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1667                 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1668                                             &nhc->nhc_gw.ipv6) < 0) {
1669                         goto nla_put_failure;
1670                 }
1671                 break;
1672         }
1673
1674         *flags |= (nhc->nhc_flags &
1675                    (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1676
1677         if (!skip_oif && nhc->nhc_dev &&
1678             nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1679                 goto nla_put_failure;
1680
1681         if (nhc->nhc_lwtstate &&
1682             lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1683                                 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1684                 goto nla_put_failure;
1685
1686         return 0;
1687
1688 nla_put_failure:
1689         return -EMSGSIZE;
1690 }
1691 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1692
1693 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1694 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1695                     int nh_weight, u8 rt_family, u32 nh_tclassid)
1696 {
1697         const struct net_device *dev = nhc->nhc_dev;
1698         struct rtnexthop *rtnh;
1699         unsigned char flags = 0;
1700
1701         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1702         if (!rtnh)
1703                 goto nla_put_failure;
1704
1705         rtnh->rtnh_hops = nh_weight - 1;
1706         rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1707
1708         if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1709                 goto nla_put_failure;
1710
1711         rtnh->rtnh_flags = flags;
1712
1713         if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1714                 goto nla_put_failure;
1715
1716         /* length of rtnetlink header + attributes */
1717         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1718
1719         return 0;
1720
1721 nla_put_failure:
1722         return -EMSGSIZE;
1723 }
1724 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1725 #endif
1726
1727 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1728 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1729 {
1730         struct nlattr *mp;
1731
1732         mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1733         if (!mp)
1734                 goto nla_put_failure;
1735
1736         if (unlikely(fi->nh)) {
1737                 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1738                         goto nla_put_failure;
1739                 goto mp_end;
1740         }
1741
1742         for_nexthops(fi) {
1743                 u32 nh_tclassid = 0;
1744 #ifdef CONFIG_IP_ROUTE_CLASSID
1745                 nh_tclassid = nh->nh_tclassid;
1746 #endif
1747                 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1748                                     AF_INET, nh_tclassid) < 0)
1749                         goto nla_put_failure;
1750         } endfor_nexthops(fi);
1751
1752 mp_end:
1753         nla_nest_end(skb, mp);
1754
1755         return 0;
1756
1757 nla_put_failure:
1758         return -EMSGSIZE;
1759 }
1760 #else
1761 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1762 {
1763         return 0;
1764 }
1765 #endif
1766
1767 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1768                   const struct fib_rt_info *fri, unsigned int flags)
1769 {
1770         unsigned int nhs = fib_info_num_path(fri->fi);
1771         struct fib_info *fi = fri->fi;
1772         u32 tb_id = fri->tb_id;
1773         struct nlmsghdr *nlh;
1774         struct rtmsg *rtm;
1775
1776         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1777         if (!nlh)
1778                 return -EMSGSIZE;
1779
1780         rtm = nlmsg_data(nlh);
1781         rtm->rtm_family = AF_INET;
1782         rtm->rtm_dst_len = fri->dst_len;
1783         rtm->rtm_src_len = 0;
1784         rtm->rtm_tos = fri->tos;
1785         if (tb_id < 256)
1786                 rtm->rtm_table = tb_id;
1787         else
1788                 rtm->rtm_table = RT_TABLE_COMPAT;
1789         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1790                 goto nla_put_failure;
1791         rtm->rtm_type = fri->type;
1792         rtm->rtm_flags = fi->fib_flags;
1793         rtm->rtm_scope = fi->fib_scope;
1794         rtm->rtm_protocol = fi->fib_protocol;
1795
1796         if (rtm->rtm_dst_len &&
1797             nla_put_in_addr(skb, RTA_DST, fri->dst))
1798                 goto nla_put_failure;
1799         if (fi->fib_priority &&
1800             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1801                 goto nla_put_failure;
1802         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1803                 goto nla_put_failure;
1804
1805         if (fi->fib_prefsrc &&
1806             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1807                 goto nla_put_failure;
1808
1809         if (fi->nh) {
1810                 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1811                         goto nla_put_failure;
1812                 if (nexthop_is_blackhole(fi->nh))
1813                         rtm->rtm_type = RTN_BLACKHOLE;
1814                 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1815                         goto offload;
1816         }
1817
1818         if (nhs == 1) {
1819                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1820                 unsigned char flags = 0;
1821
1822                 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1823                         goto nla_put_failure;
1824
1825                 rtm->rtm_flags = flags;
1826 #ifdef CONFIG_IP_ROUTE_CLASSID
1827                 if (nhc->nhc_family == AF_INET) {
1828                         struct fib_nh *nh;
1829
1830                         nh = container_of(nhc, struct fib_nh, nh_common);
1831                         if (nh->nh_tclassid &&
1832                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1833                                 goto nla_put_failure;
1834                 }
1835 #endif
1836         } else {
1837                 if (fib_add_multipath(skb, fi) < 0)
1838                         goto nla_put_failure;
1839         }
1840
1841 offload:
1842         if (fri->offload)
1843                 rtm->rtm_flags |= RTM_F_OFFLOAD;
1844         if (fri->trap)
1845                 rtm->rtm_flags |= RTM_F_TRAP;
1846         if (fri->offload_failed)
1847                 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1848
1849         nlmsg_end(skb, nlh);
1850         return 0;
1851
1852 nla_put_failure:
1853         nlmsg_cancel(skb, nlh);
1854         return -EMSGSIZE;
1855 }
1856
1857 /*
1858  * Update FIB if:
1859  * - local address disappeared -> we must delete all the entries
1860  *   referring to it.
1861  * - device went down -> we must shutdown all nexthops going via it.
1862  */
1863 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1864 {
1865         int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1866         struct net *net = dev_net(dev);
1867         struct hlist_head *head;
1868         struct fib_info *fi;
1869         int ret = 0;
1870
1871         if (!fib_info_laddrhash || local == 0)
1872                 return 0;
1873
1874         head = fib_info_laddrhash_bucket(net, local);
1875         hlist_for_each_entry(fi, head, fib_lhash) {
1876                 if (!net_eq(fi->fib_net, net) ||
1877                     fi->fib_tb_id != tb_id)
1878                         continue;
1879                 if (fi->fib_prefsrc == local) {
1880                         fi->fib_flags |= RTNH_F_DEAD;
1881                         ret++;
1882                 }
1883         }
1884         return ret;
1885 }
1886
1887 static int call_fib_nh_notifiers(struct fib_nh *nh,
1888                                  enum fib_event_type event_type)
1889 {
1890         bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1891         struct fib_nh_notifier_info info = {
1892                 .fib_nh = nh,
1893         };
1894
1895         switch (event_type) {
1896         case FIB_EVENT_NH_ADD:
1897                 if (nh->fib_nh_flags & RTNH_F_DEAD)
1898                         break;
1899                 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1900                         break;
1901                 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1902                                            &info.info);
1903         case FIB_EVENT_NH_DEL:
1904                 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1905                     (nh->fib_nh_flags & RTNH_F_DEAD))
1906                         return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1907                                                    event_type, &info.info);
1908                 break;
1909         default:
1910                 break;
1911         }
1912
1913         return NOTIFY_DONE;
1914 }
1915
1916 /* Update the PMTU of exceptions when:
1917  * - the new MTU of the first hop becomes smaller than the PMTU
1918  * - the old MTU was the same as the PMTU, and it limited discovery of
1919  *   larger MTUs on the path. With that limit raised, we can now
1920  *   discover larger MTUs
1921  * A special case is locked exceptions, for which the PMTU is smaller
1922  * than the minimal accepted PMTU:
1923  * - if the new MTU is greater than the PMTU, don't make any change
1924  * - otherwise, unlock and set PMTU
1925  */
1926 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1927 {
1928         struct fnhe_hash_bucket *bucket;
1929         int i;
1930
1931         bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1932         if (!bucket)
1933                 return;
1934
1935         for (i = 0; i < FNHE_HASH_SIZE; i++) {
1936                 struct fib_nh_exception *fnhe;
1937
1938                 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1939                      fnhe;
1940                      fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1941                         if (fnhe->fnhe_mtu_locked) {
1942                                 if (new <= fnhe->fnhe_pmtu) {
1943                                         fnhe->fnhe_pmtu = new;
1944                                         fnhe->fnhe_mtu_locked = false;
1945                                 }
1946                         } else if (new < fnhe->fnhe_pmtu ||
1947                                    orig == fnhe->fnhe_pmtu) {
1948                                 fnhe->fnhe_pmtu = new;
1949                         }
1950                 }
1951         }
1952 }
1953
1954 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1955 {
1956         struct hlist_head *head = fib_info_devhash_bucket(dev);
1957         struct fib_nh *nh;
1958
1959         hlist_for_each_entry(nh, head, nh_hash) {
1960                 if (nh->fib_nh_dev == dev)
1961                         fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1962         }
1963 }
1964
1965 /* Event              force Flags           Description
1966  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1967  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1968  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1969  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1970  *
1971  * only used when fib_nh is built into fib_info
1972  */
1973 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1974 {
1975         struct hlist_head *head = fib_info_devhash_bucket(dev);
1976         struct fib_info *prev_fi = NULL;
1977         int scope = RT_SCOPE_NOWHERE;
1978         struct fib_nh *nh;
1979         int ret = 0;
1980
1981         if (force)
1982                 scope = -1;
1983
1984         hlist_for_each_entry(nh, head, nh_hash) {
1985                 struct fib_info *fi = nh->nh_parent;
1986                 int dead;
1987
1988                 BUG_ON(!fi->fib_nhs);
1989                 if (nh->fib_nh_dev != dev || fi == prev_fi)
1990                         continue;
1991                 prev_fi = fi;
1992                 dead = 0;
1993                 change_nexthops(fi) {
1994                         if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1995                                 dead++;
1996                         else if (nexthop_nh->fib_nh_dev == dev &&
1997                                  nexthop_nh->fib_nh_scope != scope) {
1998                                 switch (event) {
1999                                 case NETDEV_DOWN:
2000                                 case NETDEV_UNREGISTER:
2001                                         nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2002                                         fallthrough;
2003                                 case NETDEV_CHANGE:
2004                                         nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2005                                         break;
2006                                 }
2007                                 call_fib_nh_notifiers(nexthop_nh,
2008                                                       FIB_EVENT_NH_DEL);
2009                                 dead++;
2010                         }
2011 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2012                         if (event == NETDEV_UNREGISTER &&
2013                             nexthop_nh->fib_nh_dev == dev) {
2014                                 dead = fi->fib_nhs;
2015                                 break;
2016                         }
2017 #endif
2018                 } endfor_nexthops(fi)
2019                 if (dead == fi->fib_nhs) {
2020                         switch (event) {
2021                         case NETDEV_DOWN:
2022                         case NETDEV_UNREGISTER:
2023                                 fi->fib_flags |= RTNH_F_DEAD;
2024                                 fallthrough;
2025                         case NETDEV_CHANGE:
2026                                 fi->fib_flags |= RTNH_F_LINKDOWN;
2027                                 break;
2028                         }
2029                         ret++;
2030                 }
2031
2032                 fib_rebalance(fi);
2033         }
2034
2035         return ret;
2036 }
2037
2038 /* Must be invoked inside of an RCU protected region.  */
2039 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2040 {
2041         struct fib_info *fi = NULL, *last_resort = NULL;
2042         struct hlist_head *fa_head = res->fa_head;
2043         struct fib_table *tb = res->table;
2044         u8 slen = 32 - res->prefixlen;
2045         int order = -1, last_idx = -1;
2046         struct fib_alias *fa, *fa1 = NULL;
2047         u32 last_prio = res->fi->fib_priority;
2048         dscp_t last_dscp = 0;
2049
2050         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2051                 struct fib_info *next_fi = fa->fa_info;
2052                 struct fib_nh_common *nhc;
2053
2054                 if (fa->fa_slen != slen)
2055                         continue;
2056                 if (fa->fa_dscp &&
2057                     fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2058                         continue;
2059                 if (fa->tb_id != tb->tb_id)
2060                         continue;
2061                 if (next_fi->fib_priority > last_prio &&
2062                     fa->fa_dscp == last_dscp) {
2063                         if (last_dscp)
2064                                 continue;
2065                         break;
2066                 }
2067                 if (next_fi->fib_flags & RTNH_F_DEAD)
2068                         continue;
2069                 last_dscp = fa->fa_dscp;
2070                 last_prio = next_fi->fib_priority;
2071
2072                 if (next_fi->fib_scope != res->scope ||
2073                     fa->fa_type != RTN_UNICAST)
2074                         continue;
2075
2076                 nhc = fib_info_nhc(next_fi, 0);
2077                 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2078                         continue;
2079
2080                 fib_alias_accessed(fa);
2081
2082                 if (!fi) {
2083                         if (next_fi != res->fi)
2084                                 break;
2085                         fa1 = fa;
2086                 } else if (!fib_detect_death(fi, order, &last_resort,
2087                                              &last_idx, fa1->fa_default)) {
2088                         fib_result_assign(res, fi);
2089                         fa1->fa_default = order;
2090                         goto out;
2091                 }
2092                 fi = next_fi;
2093                 order++;
2094         }
2095
2096         if (order <= 0 || !fi) {
2097                 if (fa1)
2098                         fa1->fa_default = -1;
2099                 goto out;
2100         }
2101
2102         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2103                               fa1->fa_default)) {
2104                 fib_result_assign(res, fi);
2105                 fa1->fa_default = order;
2106                 goto out;
2107         }
2108
2109         if (last_idx >= 0)
2110                 fib_result_assign(res, last_resort);
2111         fa1->fa_default = last_idx;
2112 out:
2113         return;
2114 }
2115
2116 /*
2117  * Dead device goes up. We wake up dead nexthops.
2118  * It takes sense only on multipath routes.
2119  *
2120  * only used when fib_nh is built into fib_info
2121  */
2122 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2123 {
2124         struct fib_info *prev_fi;
2125         struct hlist_head *head;
2126         struct fib_nh *nh;
2127         int ret;
2128
2129         if (!(dev->flags & IFF_UP))
2130                 return 0;
2131
2132         if (nh_flags & RTNH_F_DEAD) {
2133                 unsigned int flags = dev_get_flags(dev);
2134
2135                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2136                         nh_flags |= RTNH_F_LINKDOWN;
2137         }
2138
2139         prev_fi = NULL;
2140         head = fib_info_devhash_bucket(dev);
2141         ret = 0;
2142
2143         hlist_for_each_entry(nh, head, nh_hash) {
2144                 struct fib_info *fi = nh->nh_parent;
2145                 int alive;
2146
2147                 BUG_ON(!fi->fib_nhs);
2148                 if (nh->fib_nh_dev != dev || fi == prev_fi)
2149                         continue;
2150
2151                 prev_fi = fi;
2152                 alive = 0;
2153                 change_nexthops(fi) {
2154                         if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2155                                 alive++;
2156                                 continue;
2157                         }
2158                         if (!nexthop_nh->fib_nh_dev ||
2159                             !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2160                                 continue;
2161                         if (nexthop_nh->fib_nh_dev != dev ||
2162                             !__in_dev_get_rtnl(dev))
2163                                 continue;
2164                         alive++;
2165                         nexthop_nh->fib_nh_flags &= ~nh_flags;
2166                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2167                 } endfor_nexthops(fi)
2168
2169                 if (alive > 0) {
2170                         fi->fib_flags &= ~nh_flags;
2171                         ret++;
2172                 }
2173
2174                 fib_rebalance(fi);
2175         }
2176
2177         return ret;
2178 }
2179
2180 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2181 static bool fib_good_nh(const struct fib_nh *nh)
2182 {
2183         int state = NUD_REACHABLE;
2184
2185         if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2186                 struct neighbour *n;
2187
2188                 rcu_read_lock_bh();
2189
2190                 if (likely(nh->fib_nh_gw_family == AF_INET))
2191                         n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2192                                                    (__force u32)nh->fib_nh_gw4);
2193                 else if (nh->fib_nh_gw_family == AF_INET6)
2194                         n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2195                                                            &nh->fib_nh_gw6);
2196                 else
2197                         n = NULL;
2198                 if (n)
2199                         state = n->nud_state;
2200
2201                 rcu_read_unlock_bh();
2202         }
2203
2204         return !!(state & NUD_VALID);
2205 }
2206
2207 void fib_select_multipath(struct fib_result *res, int hash)
2208 {
2209         struct fib_info *fi = res->fi;
2210         struct net *net = fi->fib_net;
2211         bool first = false;
2212
2213         if (unlikely(res->fi->nh)) {
2214                 nexthop_path_fib_result(res, hash);
2215                 return;
2216         }
2217
2218         change_nexthops(fi) {
2219                 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2220                         if (!fib_good_nh(nexthop_nh))
2221                                 continue;
2222                         if (!first) {
2223                                 res->nh_sel = nhsel;
2224                                 res->nhc = &nexthop_nh->nh_common;
2225                                 first = true;
2226                         }
2227                 }
2228
2229                 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2230                         continue;
2231
2232                 res->nh_sel = nhsel;
2233                 res->nhc = &nexthop_nh->nh_common;
2234                 return;
2235         } endfor_nexthops(fi);
2236 }
2237 #endif
2238
2239 void fib_select_path(struct net *net, struct fib_result *res,
2240                      struct flowi4 *fl4, const struct sk_buff *skb)
2241 {
2242         if (fl4->flowi4_oif)
2243                 goto check_saddr;
2244
2245 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2246         if (fib_info_num_path(res->fi) > 1) {
2247                 int h = fib_multipath_hash(net, fl4, skb, NULL);
2248
2249                 fib_select_multipath(res, h);
2250         }
2251         else
2252 #endif
2253         if (!res->prefixlen &&
2254             res->table->tb_num_default > 1 &&
2255             res->type == RTN_UNICAST)
2256                 fib_select_default(fl4, res);
2257
2258 check_saddr:
2259         if (!fl4->saddr)
2260                 fl4->saddr = fib_result_prefsrc(net, res);
2261 }